With the rapid development of industry and the urbanizing tendency of the population, the emission of large amounts of chemical hazardous substances becomes an important factor threatening the natural environment and ecosystem. Hazardous heavy metals, including arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), fluorine (F), selenium (Se) and mercury (Hg), adversely affect the human body, are not decomposed in water or converted into stable compounds and remain mixed and contaminate water and soil. If these hazardous heavy metals get into and accumulate in the body through various food routes such as via fish by proceeding up the food chain and are absorbed in vivo, they bind to biological substances to form non-biodegradable organic complexes, and thus are not quickly discharged out of the body and are accumulated in organs (e.g., liver or kidneys) or bone. Thus, these hazardous heavy metals can impair the health. Particularly, because heavy metals, once accumulated in the body, are not easily released, heavy metal pollution is a threatening factor and difficult to recover from.
The world health organization (WHO) strictly regulates the concentrations of various heavy metals which are hazardous to human health in drinking water to specific concentrations or less, and in order to prevent heavy metal pollution, countermeasures, including the regulation of pollutant emission, the improvement of pollutant treatment facilities, the development and growth of clean technology, and environmental education for social members, are performed.
However, in order to fundamentally prevent heavy metal pollution, a technology capable of accurately measuring the amounts of hazardous heavy metals emitted to the environment, must be ensured, and the strict regulation of environmental pollution must be performed using this technology.
Accordingly, the importance of the development of a technology for environmental prediction, monitoring and assessment is receiving great attention, and in order to meet the demand for novel environmental measurement procedures, to effectively cope with complicated, diversified environmental problems and ensure the assaying and analytic ability for generating compliance with international standards, studies focused on improving the reliability and accuracy of environmental measurement technology must be conducted.
In industrial plants causing industrial environmental wastewater, an effective process capable of reducing environmental pollution by monitoring environmental pollution through the accurate analysis of the content of heavy metals in wastewater can be ensured.
Wastewater from chemical industries, including petrochemicals, pulp industries, oil and fat industries, paper-making industries, petroleum purification processes, plastic industries and adhesive processes, which account for more than 27% of Korean industry, contain non-biodegradable organic compounds, including nitrobenzene, chlorophenol, benzidine and phenol. Such aromatic organic compounds are introduced into the human living environment, so that they are absorbed and concentrated in organisms and cause serious ecological problems in organisms. In addition, when the analysis of heavy metals in industrial wastewater is carried out, the accuracy of analytic results is reduced due to a matrix effect caused by the formation of metal complexes between heavy metals and organic compounds.
When hazardous heavy metal concentration in environmental wastewater containing such organic compounds is measured, it is difficult to measure accurate amounts due to the matrix effect, and for this reason, various studies focusing on increasing the accuracy of measurement have been conducted. Thus, in order to analyze hazardous heavy metals in wastewater containing organic compounds, the separation and treatment of the organic compounds must be performed before the analysis.
However, aromatic organic compounds are not readily degraded through low-cost biological methods, and in most cases they are degraded through separation methods, such as a precipitation method and a solvent extraction method, and chemical methods employing acids, alkalis or the like. However, such methods are excessively time-consuming and can reduce the accuracy of analysis due to the loss of samples, which can occur in pretreatment processes, and, in addition, they can cause secondary environmental pollution.
Thus, in order to develop a method for the analysis of heavy metals in industrial wastewater, studies on the effective pretreatment of non-biodegradable organic compounds and the selective separation and concentration of heavy metals after the pretreatment are required. Also, it is required to develop small-scale systems for conducting pretreatment, concentration and measurement, which can substitute for expensive spectrophotometric analytic instruments (e.g., UV-VIS spectrophotometers, atomic absorption spectrometers, ICP atomic emission spectrometers) and which can monitor trace heavy metals on-line in situ.